Is there a performance improvement in V8 over V6.7.4

I'm currently using X1 V6.7.4 on my old Dell Precision M90 (circa 2007, Intel Core 2 Duo T7200).

Is there any improvement in performance (as opposed to features) in the new version of X1? I'm wondering if its worth spending $50 now, or better to wait till I buy a new notebook later this year. (If there's a performance improvement, I'd be willing to make the plunge now, given that my system can do with any possible improvement in CPU utilization.)

Thanks

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